1. Field of the Invention
The present invention relates to steering rack seals and more particularly to noise reduction beads for use on a steering rack seal.
2. Description of Related Art
The fluid energized rack & pinion steering system on an automobile includes a rack seal which is placed within a rack retainer and is further set against a rack bushing. In prior art systems the rack bushing is made of a metal material and the rack seal with rubber or other composite materials. When the steering system is energized the rack seal is pressed against the rack bushing and a rack seal rotate about each other staying in contact with one another at all times. However, with the push towards lighter vehicles for better gas mileage there has been a move towards replacing metal components of a car with plastic or thermoplastic materials. Such a weight reduction has been proposed by replacing the metal rack bushing with a thermoplastic bushing as a cost and weight saving reduction for the automobile. This creates a thermoplastic and rubber interface between the rack seal and the thermoplastic bushing, because of molding tolerances the thermoplastic bushing creates a gap of approximately 0.5 millimeters to 1 millimeter between the bushing face and the rack seal air side face. During the operation of the steering system the bushing face and the seal face are alternately in contact and separate from one another. This causes difficulties in that as the surfaces separate a noise of an objectionable character is generated and causes concern among the users of the automobiles. Therefore, there is a need to eliminate this noise but still allow implementation of the thermoplastic bushing in order to reduce cost and weight for the automobile manufacturer.
Therefore, there is a need in the art for a noise abating system such that during separation of a thermoplastic bushing and a rack seal an objectionable noise is not made.